Only client I/O, cluster recovery I/O and/or data scrubbing I/O make the cluster "busy". If you have removed client workloads and the cluster is healthy, it should be mostly idle. Simply having data sitting in the cluster but not being accessed or modified doesn't make the cluster do any work, except for scheduled data scrubbing. Note that depending on the data volume and the OSD performance, scrubbing may take considerable time. Monitor logs generally provide a good idea of what's going on with the cluster and whether scrubbing is active. /Z On Mon, 6 Nov 2023 at 12:48, V A Prabha <prabhav@xxxxxxx> wrote: > Please clarify my query. > I had 700+ volumes (220 applications) running in 36 OSDs when it reported > the slow operations. Due to emergency, we migrated 200+ VMs to another > virtualization environment. So we have shutdown all the related VMs in our > Openstack production setup running with Ceph. > We have not deleted the 200+ volumes from Ceph as waiting for the > concurrence from the departments. > My query is that even when the applications are down, does the volume at > the backend make our cluster busy when there is no active transactions? > Is there any parameter in the ceph osd log and ceph mon log that gives me > the clue for the cluster business? > Is there any zombie or unwanted process that make the ceph cluster busy or > the IOPS budget of the disk that makes the cluster busy? > > > On November 4, 2023 at 4:29 PM Zakhar Kirpichenko <zakhar@xxxxxxxxx> > wrote: > > You have an IOPS budget, i.e. how much I/O your spinners can deliver. > Space utilization doesn't affect it much. > > You can try disabling write (not read!) cache on your HDDs with sdparm > (for example, sdparm -c WCE /dev/bla); in my experience this allows HDDs to > deliver 50-100% more write IOPS. If there is lots of free RAM on the OSD > nodes, you can play with osd_memory_target and bluestore_cache_size_hdd OSD > options; be careful though: depending on you workload, the performance > impact may be insignificant, but your OSDs may run out of memory. > > /z > > On Sat, 4 Nov 2023 at 12:04, V A Prabha < prabhav@xxxxxxx> wrote: > > Now in this situation how can stabilize my production setup as you have > mentioned the cluster is very busy. > Is there any configuration parameter tuning will help or the only option > is to reduce the applications running on the cluster. > Though if I have free available storage of 1.6 TB free in each of my OSD, > that will not help in my IOPS issue right? > Please guide me > > On November 2, 2023 at 12:47 PM Zakhar Kirpichenko < zakhar@xxxxxxxxx> > wrote: > > >1. The calculated IOPS is for the rw operation right ? > > Total drive IOPS, read or write. Depending on the exact drive models, it > may be lower or higher than 200. I took the average for a smaller sized > 7.2k rpm SAS drive. Modern drives usually deliver lower read IOPS and > higher write IOPS. > > >2. Cluster is very busy? Is there any misconfiguration or missing tuning > paramater that makes the cluster busy? > > You have almost 3k IOPS and your OSDs report slow ops. I'd say the cluster > is busy, as in loaded with I/O, perhaps more I/O than it can handle well. > > >3. Nodes are not balanced? you mean to say that the count of OSDs in > each server differs. But we have enabled autoscale and optimal distribution > so that you can see from the output of ceph osd df tree that is count of > pgs(45/OSD) and use% (65 to 67%). Is that not significant? > > Yes, the OSD count differs. This means that the CPU, memory usage, network > load and latency differ per node and may cause performance variations, > depending on your workload. > > /Z > > On Thu, 2 Nov 2023 at 08:18, V A Prabha < prabhav@xxxxxxx> wrote: > > Thanks for your prompt reply .. > But the query is > 1.The calculated IOPS is for the rw operation right ? > 2. Cluster is very busy? Is there any misconfiguration or missing tuning > paramater that makes the cluster busy? > 3. Nodes are not balanced? you mean to say that the count of OSDs in each > server differs. But we have enabled autoscale and optimal distribution so > that you can see from the output of ceph osd df tree that is count of > pgs(45/OSD) and use% (65 to 67%). Is that not significant? > Correct me if my queries are irrelevant > > > > On November 2, 2023 at 11:36 AM Zakhar Kirpichenko < zakhar@xxxxxxxxx> > wrote: > > Sure, it's 36 OSDs at 200 IOPS each (tops, likely lower), I assume size=3 > replication so 1/3 of the total performance, and some 30%-ish OSD > overhead. > > (36 x 200) * 1/3 * 0.7 = 1680. That's how many IOPS you can realistically > expect from your cluster. You get more than that, but the cluster is very > busy and OSDs aren't coping. > > Also your nodes are not balanced. > > /Z > > On Thu, 2 Nov 2023 at 07:33, V A Prabha < prabhav@xxxxxxx> wrote: > > Can you please elaborate your identifications and the statement . > > > On November 2, 2023 at 9:40 AM Zakhar Kirpichenko < zakhar@xxxxxxxxx> > wrote: > > I'm afraid you're simply hitting the I/O limits of your disks. > > /Z > > On Thu, 2 Nov 2023 at 03:40, V A Prabha < prabhav@xxxxxxx> wrote: > > Hi Eugen > Please find the details below > > > root@meghdootctr1:/var/log/ceph# ceph -s > cluster: > id: c59da971-57d1-43bd-b2b7-865d392412a5 > health: HEALTH_WARN > nodeep-scrub flag(s) set > 544 pgs not deep-scrubbed in time > > services: > mon: 3 daemons, quorum meghdootctr1,meghdootctr2,meghdootctr3 (age 5d) > mgr: meghdootctr1(active, since 5d), standbys: meghdootctr2, meghdootctr3 > mds: 3 up:standby > osd: 36 osds: 36 up (since 34h), 36 in (since 34h) > flags nodeep-scrub > > data: > pools: 2 pools, 544 pgs > objects: 10.14M objects, 39 TiB > usage: 116 TiB used, 63 TiB / 179 TiB avail > pgs: 544 active+clean > > io: > client: 24 MiB/s rd, 16 MiB/s wr, 2.02k op/s rd, 907 op/s wr > > > Ceph Versions: > > root@meghdootctr1:/var/log/ceph# ceph --version > ceph version 14.2.16 (762032d6f509d5e7ee7dc008d80fe9c87086603c) nautilus > (stable) > > Ceph df -h > https://pastebin.com/1ffucyJg > > Ceph OSD performance dump > https://pastebin.com/1R6YQksE > > Ceph tell osd.XX bench (Out of 36 osds only 8 OSDs give High IOPS value > of 250 > +. Out of that 4 OSDs are from HP 3PAR and 4 OSDS from DELL EMC. We are > using > only 4 OSDs from HP3 par and it is working fine without any latency and > iops > issues from the beginning but the remaining 32 OSDs are from DELL EMC in > which 4 > OSDs are much better than the remaining 28 OSDs) > > https://pastebin.com/CixaQmBi > > Please help me to identify if the issue is with the DELL EMC Storage, Ceph > configuration parameter tuning or the Overload in the cloud setup > > > > On November 1, 2023 at 9:48 PM Eugen Block < eblock@xxxxxx> wrote: > > Hi, > > > > for starters please add more cluster details like 'ceph status', 'ceph > > versions', 'ceph osd df tree'. Increasing the to 10G was the right > > thing to do, you don't get far with 1G with real cluster load. How are > > the OSDs configured (HDD only, SSD only or HDD with rocksdb on SSD)? > > How is the disk utilization? > > > > Regards, > > Eugen > > > > Zitat von prabhav@xxxxxxx: > > > > > In a production setup of 36 OSDs( SAS disks) totalling 180 TB > > > allocated to a single Ceph Cluster with 3 monitors and 3 managers. > > > There were 830 volumes and VMs created in Openstack with Ceph as a > > > backend. On Sep 21, users reported slowness in accessing the VMs. > > > Analysing the logs lead us to problem with SAS , Network congestion > > > and Ceph configuration( as all default values were used). We updated > > > the Network from 1Gbps to 10Gbps for public and cluster networking. > > > There was no change. > > > The ceph benchmark performance showed that 28 OSDs out of 36 OSDs > > > reported very low IOPS of 30 to 50 while the remaining showed 300+ > > > IOPS. > > > We gradually started reducing the load on the ceph cluster and now > > > the volumes count is 650. Now the slow operations has gradually > > > reduced but I am aware that this is not the solution. > > > Ceph configuration is updated with increasing the > > > osd_journal_size to 10 GB, > > > osd_max_backfills = 1 > > > osd_recovery_max_active = 1 > > > osd_recovery_op_priority = 1 > > > bluestore_cache_trim_max_skip_pinned=10000 > > > > > > After one month, now we faced another issue with Mgr daemon stopped > > > in all 3 quorums and 16 OSDs went down. From the > > > ceph-mon,ceph-mgr.log could not get the reason. Please guide me as > > > its a production setup > > > _______________________________________________ > > > ceph-users mailing list -- ceph-users@xxxxxxx > > > To unsubscribe send an email to ceph-users-leave@xxxxxxx > > > > > > _______________________________________________ > > ceph-users mailing list -- ceph-users@xxxxxxx > > To unsubscribe send an email to ceph-users-leave@xxxxxxx > Thanks & Regards, > Ms V A Prabha / श्रीमती प्रभा वी ए > Joint Director / संयुक्त निदेशक > Centre for Development of Advanced Computing(C-DAC) / प्रगत संगणन विकास > केन्द्र(सी-डैक) > Tidel Park”, 8th Floor, “D” Block, (North &South) / “टाइडल पार्क”,8वीं > मंजिल, > “डी” ब्लॉक, (उत्तर और दक्षिण) > No.4, Rajiv Gandhi Salai / नं.4, राजीव गांधी सलाई > Taramani / तारामणि > Chennai / चेन्नई – 600113 > Ph.No.:044-22542226/27 > Fax No.: 044-22542294 > ------------------------------------------------------------------------------------------------------------ > > [ C-DAC is on Social-Media too. 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Any unauthorized review, use, > disclosure, dissemination, forwarding, printing or copying of this email > is strictly prohibited and appropriate legal action will be taken. > ------------------------------------------------------------------------------------------------------------ > > > > > Thanks & Regards, > Ms V A Prabha / श्रीमती प्रभा वी ए > Joint Director / संयुक्त निदेशक > Centre for Development of Advanced Computing(C-DAC) / प्रगत संगणन विकास > केन्द्र(सी-डैक) > Tidel Park”, 8th Floor, “D” Block, (North &South) / “टाइडल पार्क”,8वीं > मंजिल, “डी” ब्लॉक, (उत्तर और दक्षिण) > No.4, Rajiv Gandhi Salai / नं.4, राजीव गांधी सलाई > Taramani / तारामणि > Chennai / चेन्नई – 600113 > Ph.No.:044-22542226/27 > Fax No.: 044-22542294 > > ------------------------------------------------------------------------------------------------------------ > > [ C-DAC is on Social-Media too. Kindly follow us at: > Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ] > > This e-mail is for the sole use of the intended recipient(s) and may > contain confidential and privileged information. If you are not the > intended recipient, please contact the sender by reply e-mail and destroy > all copies and the original message. Any unauthorized review, use, > disclosure, dissemination, forwarding, printing or copying of this email > is strictly prohibited and appropriate legal action will be taken. > ------------------------------------------------------------------------------------------------------------ > > > > > Thanks & Regards, > Ms V A Prabha / श्रीमती प्रभा वी ए > Joint Director / संयुक्त निदेशक > Centre for Development of Advanced Computing(C-DAC) / प्रगत संगणन विकास > केन्द्र(सी-डैक) > Tidel Park”, 8th Floor, “D” Block, (North &South) / “टाइडल पार्क”,8वीं > मंजिल, “डी” ब्लॉक, (उत्तर और दक्षिण) > No.4, Rajiv Gandhi Salai / नं.4, राजीव गांधी सलाई > Taramani / तारामणि > Chennai / चेन्नई – 600113 > Ph.No.:044-22542226/27 > Fax No.: 044-22542294 > > ------------------------------------------------------------------------------------------------------------ > > [ C-DAC is on Social-Media too. Kindly follow us at: > Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ] > > This e-mail is for the sole use of the intended recipient(s) and may > contain confidential and privileged information. If you are not the > intended recipient, please contact the sender by reply e-mail and destroy > all copies and the original message. Any unauthorized review, use, > disclosure, dissemination, forwarding, printing or copying of this email > is strictly prohibited and appropriate legal action will be taken. > ------------------------------------------------------------------------------------------------------------ > > > > > Thanks & Regards, > Ms V A Prabha / श्रीमती प्रभा वी ए > Joint Director / संयुक्त निदेशक > Centre for Development of Advanced Computing(C-DAC) / प्रगत संगणन विकास > केन्द्र(सी-डैक) > Tidel Park”, 8th Floor, “D” Block, (North &South) / “टाइडल पार्क”,8वीं > मंजिल, “डी” ब्लॉक, (उत्तर और दक्षिण) > No.4, Rajiv Gandhi Salai / नं.4, राजीव गांधी सलाई > Taramani / तारामणि > Chennai / चेन्नई – 600113 > Ph.No.:044-22542226/27 > Fax No.: 044-22542294 > > ------------------------------------------------------------------------------------------------------------ > > [ C-DAC is on Social-Media too. Kindly follow us at: > Facebook: https://www.facebook.com/CDACINDIA & Twitter: @cdacindia ] > > This e-mail is for the sole use of the intended recipient(s) and may > contain confidential and privileged information. If you are not the > intended recipient, please contact the sender by reply e-mail and destroy > all copies and the original message. Any unauthorized review, use, > disclosure, dissemination, forwarding, printing or copying of this email > is strictly prohibited and appropriate legal action will be taken. > ------------------------------------------------------------------------------------------------------------ > > _______________________________________________ ceph-users mailing list -- ceph-users@xxxxxxx To unsubscribe send an email to ceph-users-leave@xxxxxxx
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